Vapor generator



R. H. EVANS VAPOR GENERATOR Oct; 1, 1963 4 Sheets-Sheet 1 Filed July 11,1960 Inventor Richard Henry Evans 4 Attorney Oct. 1, 1963 R. H. EVANS3,105,466

VAPOR GENERATOR Filed July 11, 1960 4 Sheets-Sheet 2 v In venlor A Homey R. H. EVANS 3,105,466

VAPOR GENERATOR Oct. 1, 1963 4 Sheets -Sheet 51 Filed July 11, 1960 Inventor- A (torn e y Oct. 1, 1963,

Filed July 11, 1960 R. H. Ev-A'Ns Y 3,105,466

VAPOR GENERATOR 4 Shee ts-Sheet 4 Inventor Attorney United States Patent@h ice Edd-5,466 Patented Get. 1,1963

3,105,466 VAPGR GENERATGR Richard Henry Evans, Surrey, England, assignorto Babcock & Wilcox, Limited, London, England, a company of GreatBritain Filed July 11, 1969, Ser. No. 52,329 Claims priority,application Great Britain July 10, 1959 Claims. (Cl. 122-235) Thisinvention relates to vapour generators of the kind having an uprightfurnace chamber provided with a firing zone in a lower region of thechamber and with a hopper bottom. Owing to the high rate of radiation tothe hopper bottom walls in the neighbourhood of the firing zone it isdesirable to line the hopper with contiguous wall tubes. In naturalcirculation boilers the tube lengths lining the hopper bottom walls aredownward extensions of the upright furnace chamber wall tubes. Such atube arrangement may also be adopted in the case of a forced flowboiler. In a forced flow boiler, however, the possibility arises ofusing horizontal tubes and the use of horizontal tubes sometimes ottersadvantages. More particularly, this invention is related to a forcedflow tubulous boiler having circuits connected in parallel for flow ofworking medium and an upright furnace chamber space with walls lined bytube lengths of the circuits, wherein the tubulous lining has sectionsextending over respective zones one above the other and each formed byhorizontal or substantially horizontal tube lengths of the respectivecircuits, the tube lengths of the circuim being distributed in the zonesin a manner adapted to give approximately equal heat inputs to thecircuits.

When furnace chamber wall areas are lined by horizontal or substantiallyhorizontal tube lengths it is desirable that at least upper parts ofhopper bottom wall areas should also be lined with horizontal orsubstantially horizontal contiguous tube lengths and it is importantthat the tubes should be drainable. If, as is usual, pairs of oppositehopper walls are respectively vertical and inclined, diificulty arisesin maintaining both drainability of the tubes and contact betweenadjacent tubes.

A vapour generator according to the present invention includes anupright furnace chamber, a firing zone in a lower region of the chamber,horizontal or substantially horizontal tube lengths arranged to operatewith forced flow of the working medium therethrough lining areas of thefurnace chamber walls and wall areas of a furnace chamber hopper bottom,tube lengths over at least an upper part of the furnace chamber hopperbottom being contiguously arranged to define wall surfaces of theseveral walls which surfaces slope at the same or substantially the sameinclination.

The invention will now be described, by way of example, with referenceto the accompanying, partly diagrammatic drawings, in which:

FIGURE 1 is an isometric elevation of a lower part of a steam generatingand superheating unit having a hopper bottom;

FIGURE 2 is a fragmentary sectional elevation taken on the line 11-11 ofFIGURE 1;

FIGURE 3 is a fragmentary sectional elevation taken on the line III-J11of FIGURE 1;

FIGURE 4 is an isometric elevation of an alternative arrangement of ahopper bottom of a steam generating and superheating unit;

FIGURE 5 is a front elevation of an alternative arrangement of tubeslining a hopper bottom; and

FIGURE 6 is a sectional side elevation taken on the line VI-VI of FIGURE1.

A furnace chamber 2 of a steam generating and superheating unit, a lowerportion of which is shown in FIG- URE 1, is lined with tubes 4 connectedinto the fluid circulation system of a forced-flow tubulous boilerhaving circuits connected in parallel for the flow of working medium.The walls of the furnace chamber 2 are lined with horizontal tubelengths of the circuits located in sections extending over respectivezones one above the other, the tube lengths being arranged in groupsproviding sets 6 of adjacent tube length ends distributed around thefurnace chamber 2. The sets 6 of tube length ends each includes inletends and outlet ends and upright transfer or connector tubes 8 leadingto the inlet ends of each of the said sets 6 are coupled to superjacenttransfer or connector tubes 8 leading from the outlet ends of the set,the said transfer or connector tubes 8 constituting part of suspensionmeans for the section. The transfer or connector tubes 8 are arranged invertically extending sets distributed around the furnace chamber 2.

The furnace chamber 2 includes a firing zone 10 at which a front wall 12is provided with burner ports 14. In the neighbourhood of the ports 14the wall 12 is lined with a group 16 of upright tubes extending betweena lower header 15 and an upper header 17. Those of the horizontal tubes4 lying intermediate the ports 14 extend horizontally transversely ofthe group 16 of upright tubes. Others of the tubes 4 at the levels ofthe ports 14 are bent outwardly and upwardly at one side of the group 16and extend across the front wall 12 clear of the burners andintermediate the ports 14. The tubes are further bent upwardly andinwardly to re-enter the front wall 12 adjacent the other side of thegroup 16 of upright tubes at a higher level.

A hopper bottom 13 is provided with tubes 2% lining the walls thereof,the tubes in an upper portion 22 being arranged contiguously. The fourwalls of the upper portion 22 of the hopper 18 slope inwardly in adownward direction at similar inclinations. The front wall 24 of thehopper bottom 18, at a level somewhat below the mid-plane in the heightof the hopper bottom, continues downwardly at a reversed slope to formthe front wall of a lower portion 25 at an inclination substantiallyequal to that of the upper portion of the wall. The rear wall 26continues downwardly at the same slope to a somewhat lower level therethe wall continuing downwardly with a reversed slope having aninclination substantially equal to that of the upper portion of the wallso that the lower extremities of the front and rear walls flareoutwardly. The side walls 27 at the level of the change of slope of thefront walls 2 continue downwardly in a vertical plane.

The tubes 20 lining the hopper bottom 18 are arranged in eight parallelpasses 28, each pass extending upwardly from a lower, drainable,distributor 30 in a sinuous or meandering manner to upper, drainable,collectors 32 discharging through connectors 33 to a lower distributor34.

Each pass 28 includes horizontally extending tube lengths arranged inparallel flow relationship in legs A, B, C, D, E, F, G and H, respectiveends of tube lengths of adjacent legs being connected by upright tubeportions.

As shown in FIGURE 2, the front and rear walls 24, 26 are lined with thetubes 20 arranged in spaced rela tionship in the lower legs A, B and incontiguous relationship in the upper legs C, D, E, F, G, H. The tubes inthe lower legs A, B are provided with longitudinal fins 38 extendinginto the gaps between the tubes. Alternatively, the tubes may beprovided with studs and the gaps filled with refractory material. Sincethe tubes 20 of the lowermost leg A are spaced apart, respective tubescan be connected with horizontally extending tube lengths 36, the slopeof the wall and the spacing of the tubes in the wall being such thatthere is no interference between a tube length 36 connecting with one ofthe tubes 20 and 3 an adjacent tube length 36 connecting with anadjacent tube 20, and tubes 20 arranged in spaced relationship in thewall when bent at right angles to lie with their axes in a verticalplane are arranged contiguously. Respective tubes 20 of the uppermostleg H are connected with tube lengths 4t) discharging to the uppercollector 32. Since the tubes 29 in the uppermost leg H are arrangedcontiguously, the tube lengths 46 extend downwardly from the leg H withtheir axes perpendicular to the plane containing the axes of the tubes20 in the uppermost leg H, thereby avoiding interference betweenadjacent tube lengths 40 and tubes 20.

As shown in FIGURE 3, the side walls 27 are lined with the tubes 20arranged contiguously. Since the lower parts of the walls 27 lined bythe lower legs A, B are vertical, respective tubes 2% connect with thehorizontal tube lengths 36 without interference between adjacent tubes20 and the tube lengths 36. Parts 29 of the tubes 20 of the lower legsA, B extending into the front and rear walls 24, 26 are arranged inspaced relationship due to the axes of the tubes 20 lining the lowerparts of the side walls 27 being in vertical planes and the axes of thetubes lining the lower parts of the front and rear walls 24, 26 being inplanes inclined to the vertical. The parts 29 of the tubes 20 areprovided with longitudinal fins or studs and refractory material fillingthe gaps between the parts. Respective contiguously arranged tubes 20 ofthe uppermost leg H are connected with the tube lengths 40 extendingdownwardly from the leg H with their axes perpendicular to the planecontaining the axes of the tubes 20 in the uppermost leg H, therebyavoiding interference between adjacent tube lengths 40 and tubes 20.

In operation, feed water is supplied from economizers (not shown) to thelower header of the upright tube group 16 and is discharged to the upperheader 17. From the upper header 17 the Water flows through connectors41 to the lower distributor 30 and flows, in parallel passes, throughthe tubes lining the hopper 18 to the upper collectors 32 whichdischarge to the lower distributor 34. The water then flows, in parallelpasses, through the transfer tubes 8 to the tubes 4 lining the furnacechamber 2, the flow being in a generally upward direction, the tubesdischarging to upper headers (not shown) connecting with the remainingparts of the unit.

It will be understood that by sloping all of the walls of the upperportion 22 of the hopper 18 at the same inward inclination, the tubeslining the upper portion 22 may be arranged contiguously therebyachieving an economy in cost over an arrangement in which the tubes arespaced apart and require the provision of suitable fins or studs andrefractory material to fill the gaps between tubes. Since the tubelengths 36 of the tubes 20 extend horizontally and downwardly into thelower, drainable, distributor and the tube lengths 40 extend downwardlyinto the upper, drainable, collector 32, complete draining of the tubes20 is possible.

In the alternative arrangement of a hopper bottom shown in FIGURE 4, ahopper bottom 42 is lined with tubes 44 and is formed with an upperportion 46 having walls sloping inwardly in a downward direction atsimilar inclinations and lined with the tubes 44 arranged contiguously.The front wall 48 of the hopper 42, at a level somewhat below themid-plane in the height of the hopper, continues downwardly at areversed slope having an inclination substantially equal to that of thepart of the front wall in the upper portion 46. At a somewhat lowerlevel the rear wall 50 also continues downwardly with a reversed slopesubstantially equal to that of the part of the rear wall in the upperportion 46 so that the 7 lower extremities of the front and rear walls48 and 50 flare outwardly, Below the level of the upper portion 46 ofthe hopper 42 the side walls 51 extend downwardly in vertical planes.Below the level of the upper portion 46 the tubes 44 are arranged inspaced relationship in the front and rear walls 48, 50 the gaps betweenthe tubes being filled with longitudinal fins or with studs andrefractory material, and in continguous relationship in the side walls5-1.

The tubes 44 lining the hopper 42 are arranged in a number of parallelpasses, two tubes lengths 52, 54 of a pass only being shown for the sakeof clarity. The tube lengths 52, 54 extend upwardly from a lower,drainable, distributor 56 and horizontally into the front wall 48 of thehopper 42 to extend in opposite directions around the hopper to transferportions 58, 60 extending horizontally from the rear wall and upwardlyto the upper portion 46 of the hopper bottom 18, parts 59, 61 of thetube portions 53, 6% connecting into the rear wall 50 being arrangednormal to the rear wall. The tube lengths 52, 54 then extend in oppositedirections around the upper portion 46 of the hopper 42 to connectorportions 62, 64 arranged normal to the front wall 48 and leading fromthe front wall to a drainable collector 66. The collector 66 dischargesthrough transfer tubes 68 to a distributor 70 connected with theremainder of the unit.

In operation water is supplied to the distributor 56, flows in agenerally upward direction through the tubes 44 lining the hopper 42 andis discharged to the collector 66 which in turn discharges to thedistributor 70'.

It will be understood that, as in the arrangement previously described,sloping of all of the walls of the upper portion 46 of the hopper 42 atthe same inclination permits contiguous arrangement of the tubes '44lining the upper portion 46, thereby achieving an economy in cost overan arrangement in which the tubes are spaced apart and require theprovision of suitable fins or studs and refractory material to fill thegaps between the tubes. Also, since the tubes 44 extend upwardly fromthe lower, drainable, distributor 56 and connecting portions of thetubes 44 extend downwardly to the drainable collectors 66, completedraining of the tubes is possible.

In the tube arrangement shown in FIGURES 5 and 6 of the drawings, tubes72 lining a hopper bottom are arranged in eight parallel passes, one ofwhich is shown in FIGURES 5 land 6, and which ascend the walls of thehopper bottom in a sinuous or meandering manner similar to that shown inFIGURE 1. The hopper bottom is formed with an upper part, the four wallsof which extend downwardly and inwardly at the same inclination, and alower part, the four walls of which extend downwardly and outwardly atthe same inclination.

The tubes 72 extend alternately upwardly from opposite sides of adrainable inlet header 74, then extend horizontally into a wall 76 andare bent in an upward direction to lie in the plane of the adjacent partof the wall, the tubes being positioned in a contiguous manner. Thetubes 72 are then bent to extend horizontally to form a first leg 78 ofa pass 80 lining a part of the wall 76.

At the top of the hopper bottom wall 76, the tubes 72 included in a lastleg 82 of the pass 80 are bent to extend upwardly in the plane of thewall and are then bent to extend horizontally outwardly from the wall76. The tubes 72 are then bent upwardly to connect alternately intoopposite sides of an outlet header 84.

The remaining parts of the walls of the hopper bottom are lined in alike manner by further tubes 72 arranged in other passes similar to thepass 80.

Since all of the walls of the upper portion 86 of the hopper bottom,extend at the same downward and inward inclination, and since all of thewalls of the lower portion 88 of the hopper bottom extend at the samedownward and outward inclination, the tubes 72 maybe arrangedcontiguously throughout their lengths lining the walls of the hopperbottom, thereby achieving an economy in cost over an arrangement inwhich some or all of the tubes are spaced apart and require theprovision of suitable fins or studs and refractory material to fill thegaps between the tubes. Also, since the tubes 72 extend in a generallyupward direction from the d-rainable inlet header 74 to the outletheader 84, complete draining of the tubes is possible.

I claim:

1. In combination with a vapor generator, means forming a furnaceconfining high temperature gases, walls forming a hopper opening to thelower end of said furnace and having a lower portion of graduallydecreasing horizontal cross-sectional area in an upward direction and anupper portion of gradually increasing horizontal crosssectional area inan upward direction, each of the wall surfaces of said upper and lowerportions of the hopper including a group of horizontally extendingvertically spaced drainable fluid cooled tube lengths arranged forparallel flow of fluid therethrough, all the wall surfaces of said upperportion of the hopper sloping at substantially the same inclination andthe tube lengths of the wall surfaces of the upper portion of the hopperbeing contiguously arranged, header means supplying fluid in parallelflow relation to the groups of tube lengths of the wall surfaces of thelower portion of the hopper, drainable tubular means connecting eachgroup of tube lengths of each wall surface of the lower portion of thehopper for series flow of fluid to the group of tube lengths of thecorresponding wall surface of the upper portion of the hopper andproviding a flow of fluid continuously in an upward direction betweenthe tube lengths of the walls of the lower and upper portions of thehopper, and means supplying fluid to said header means.

2. In combination with a vapor generator, means forming a furnaceconfining high temperature gases, walls forming a hopper opening to thelower end of said furnace and having a lower portion of graduallydecreasing horizontal cross-sectional area in an upward direction and anupper portion of gradually increasing horizontal crosssectional area inan upward direction, each of the wall surfaces of said upper and lowerportions of the hopper including a group of horizontally extendingdrainable fluid cooled tube lengths arranged for parallel flow of fluidtherethrough, all the wall surfaces of said upper portion of the hoppersloping at substantially the same inclination, a continuous headersupplying fluid in parallel flow relation to the groups of tube lengthsof the wall surfaces of the lower portion of the hopper, drainabletubular means connecting each group of tube lengths of each wall surfaceof the lower portion of the hopper for series flow of fluid to the groupof tube lengths of the corresponding wall surface of the upper portionof the hopper and providing a flow of fluid continuously in an upwarddirection between the tube lengths of the walls of the lower and upperportions of the hopper, means supplying fluid to said continuous header,and a plurality of collector headers, and sets of connector tubes eachextending normal to and connecting a group of the tube lengths of thewall surfaces of the upper portion of the hopper for flow of fluid toone of said collector headers.

3. In combination with a vapor generator, means forming a furnaceconfining high temperature gases, walls forming a hopper opening to thelower end of said furnace and having a lower portion of graduallydecreasing horizontal cross-sectional area in an upward direction and anupper portion of gradually increasing horizontal cross-sectional area inan upward direction, each of the wall surfaces of said upper and lowerportions of the hopper including a group of horizontally extendingvertically spaced drainable fluid cooled tube lengths arranged forparallel flow of fluid therethrough, all the wall surfaces of said upperportion of the hopper sloping at substantially the same inclination andthe tube lengths of the wall surfaces of the upper portion of the hopperbeing contiguously arranged, header means supplying fluid in parallelflow relation to the groups of tube lengths of the wall surfaces of thelower portion of the hopper, drainable tubular means connecting eachgroup of tube lengths of each wall surface of the lower portion of thehopper for series flow of fluid to the group of tube lengths of thecorresponding wall surface of the upper portion of the hopper, and meanssupplying fluid to said header means, the front and rear walls of thelower portion of said hopper converging in an upward direction and thetube lengths thereof being arranged in spaced relationship and havingtheir intertube spaces closed by metallic fins, the side walls of thelower portion of said hopper being vertically arranged and the tubelengths thereof being contiguously arranged.

4. In combination with a vapor generator, means forming a furnaceconfining high temperature gases, walls forming a hopper opening to thelower end of said furnace and having a lower portion of graduallydecreasing horizontal cross-sectional area in an upward direction and anupper portion of gradually increasing horizontal cross-sectional area inan upward direction, each of the wall surfaces of said upper and lowerportions of the hopper including horizontally extending verticallyspaced drainable fluid cooled tube lengths arranged for parallel flow offluid therethrough, all of the Wall surfaces of the lower portion of thehopper sloping upwardly and inwardly at substantially the sameinclination, all the wall surfaces of said upper portion of the hoppersloping upwardly and outwardly at substantially the same inclination andthe tube lengths of the wall surfaces of the upper portion of the hopperbeing contiguously arranged, header means supplying fluid in parallelflow relation to the groups of tube lengths of the wall surfaces of thelower portion of the hopper, drainable tubular means connecting eachgroup of tube lengths of each wall surface of the lower portion of thehopper for series flow of fluid to the group of tube lengths of thecorresponding wall surface of the upper portion of the hopper andproviding a flow of fluid continuously in an upward direction betweenthe tube lengths of the walls of the lower and upper portions of thehopper, and means supplying fluid to said header means.

5. in combination with a vapor generator, means forming a furnaceconfining high temperature gases, walls forming a hopper opening to thelower end of said furnace and having a lower portion of graduallydecreasing horizontal cross-sectional area in an upward direction and anupper portion of gradually increasing horizontal cross-section area inan upward direction, each of the walls of said upper and lower portionsof the hopper being lined by horizontally extending vertically spaceddrainable fluid cooled tube lengths, means interconnecting the tubelengths of each of the walls of the lower portion of the hopper forseries flow of fluid to the tube lengths of one of the walls of theupper portion of the hopper and providing a flow of fluid continuouslyin an upward direction between the tube lengths of the walls of thelower and upper portions of the hopper, and means supplying fluid to thetube lengths of the walls of the lower portion of the hopper.

References Cited in the file of this patent UNITED STATES PATENTS3,007,459 Koch Nov. 7, 1961 FOREEGN PATENTS 1,154,626 France Nov. 4,1957 1,185,795 France Feb. 16, 1959 OTHER REFERENCES German application1,054,642 printed April 9, 1959 (K1. 241 8).

1. IN COMBINATION WITH A VAPOR GENERATOR, MEANS FORMING A FURNACE CONFINING HIGH TEMPERATURE GASES, WALLS FORMING A HOPPER OPENING TO THE LOWER END OF SAID FURNACE AND HAVING A LOWER PORTION OF GRADUALLY DECREASING HORIZONTAL CROSS-SECTIONAL AREA IN AN UPWARD DIRECTION AND AN UPPER PORTION OF GRADUALLY INCREASING HORIZONTAL CROSSSECTIONAL AREA IN AN UPWARD DIRECTION, EACH OF THE WALL SURFACES OF SAID UPPER AND LOWER PORTIONS OF THE HOPPER INCLUDING A GROUP OF HORIZONTALLY EXTENDING VERTICALLY SPACED DRAINABLE FLUID COOLED TUBE LENGTHS ARRANGED FOR PARALLEL FLOW OF FLUID THERETHROUGH, ALL THE WALL SURFACES OF SAID UPPER PORTION OF THE HOPPER SLOPING AT SUBSTANTIALLY THE SAME INCLINATION AND THE TUBE LENGTHS OF THE WALL SURFACES OF THE UPPER PORTION OF THE HOPPER BEING CONTIGUOUSLY ARRANGED, HEADER MEANS SUPPLYING FLUID IN PARALLEL FLOW RELATION TO THE GROUPS OF TUBE LENGTHS OF THE WALL SURFACES OF THE LOWER PORTION OF THE HOPPER, DRAINABLE TUBULAR MEANS CONNECTING EACH GROUP OF TUBE LENGTHS OF EACH WALL SURFACE OF THE LOWER PORTION OF THE HOPPER FOR SERIES FLOW OF FLUID TO THE GROUP OF TUBE LENGTHS OF THE CORRESPONDING WALL SURFACE OF THE UPPER PORTION OF THE HOPPER AND PROVIDING A FLOW OF FLUID CONTINUOUSLY IN AN UPWARD DIRECTION BETWEEN THE TUBE LENGTHS OF THE WALLS OF THE LOWER AND UPPER PORTIONS OF THE HOPPER, AND MEANS SUPPLYING FLUID TO SAID HEADER MEANS. 